GB2116679A

GB2116679A - Shut-off or throttle valve for gaseous media

Info

Publication number: GB2116679A
Application number: GB08306772A
Authority: GB
Inventors: Rudolf Muller; Hermann-Josef Stolberg
Original assignee: Hermann Rappold and Co GmbH
Current assignee: Hermann Rappold and Co GmbH
Priority date: 1982-03-12
Filing date: 1983-03-11
Publication date: 1983-09-28
Also published as: DE3208906C2; US4527773A; DE3208906A1; GB8306772D0; FR2523252A1; AU1242783A; AU556468B2; FR2523252B3; IN158607B; NL8300862A; JPS58163873A; ZA831701B; IT8347679A0; IT1164608B; GB2116679B

Description

1 GB 2 116 679 A 1

SPECIFICATION

Shut-off or throttle valve for gaseous media The invention relates to a shut-off or throttle valve for gaseous media and is concerned with that type of valve in which the seal is carried by the valve housing and/or the valve member and comprises a resilient strip carried in a bent configuration by a frame profile.

The use of such valves, in the form of either a flap valve or a gate valve, is known, particularly in connection with hot and dust-laden gases.

In the known valves of this type, the seal, prior to its incorporation in the valve, has either a closed tubular profile (DE- GM 66 08 115) or an open half-tubular profile (DE-PS 10 96 134, DE-OS 26 15 817, DE-OS 27 16 744). These known seals are expensive as regards manufacture and ease of assembly and frequently have the disadvantage that they do not have the elastic deformability necessary to achieve a satisfactory seal.

It is an object of the invention to provide a shut-off orthrottle valve of the type referred to above which has a seal which may be easily manufactured and assembled and which is readily deformable in operation without the elastic limit being exceeded.

According to the present invention there is provided a valve for gaseous media including a valve housing and a substantially planar valve member which is movable with respect to the housing to throttle or shut off gas flow therethrough, the housing and/or the valve member carrying a seal arranged to form a substantially gas-tight seal, when the valve member is in the closed position, with a sealing surface, the or each seal comprising a frame profile having two limbs which are directed towards the associated sealing surface when the valve member is in the closed position and a resilient sealing strip which is bent and so positioned that its longitudinal edges freely engage the said limbs and its central portion forms an arch extending out of the space defined by the said limbs.

To manufacture the seal, a strip of appropriate breadth of a suitable, elastic metal plate or similar material is required. This flat sealing strip is fitted into the frame profile by bending the strip by hand or by means of a simple mechanical device. The sealing strip engages the interior surface of the limbs of the frame profile under the action of its resilience and thus adopts the shape of an elastic arch in the sealing region with the limbs of the frame profile extending approximately tangentially to this arch. The seal will thus comprise one or more substantial- ly linear sections and if the sealing strip is removed from the frame profile it will return substantially to its original flat shape under the action of its resilience. When the seal is stressed by the opposing sealing surface of the valve, that is to say when the arch contacts the opposing sealing surface, the sealing strip yields in the arch region and thus produces the necessary sealing pressure against the opposing sealing surface contacting it.

The seal in accordance with the invention exhibits satisfactory sealing characteristics with the sealing seat because even when there are surface irregularities present at the sealing seat, the sealing strip can always engage the opposing sealing surface cooperating with it in a substantially gas-tight manner over a relatively broad surface.

The proposed construction has the further advantage that the sealing strip is held against the limbs of the frame profile only by the contact pressure between them resulting from the resilience of the strip so that special securing means for retaining the sealing strip,in the frame profile are unnecessary. Thus, even with thermally stressed valves it is possible to use relatively long sealing strips since these can expand freely within the frame profile.

This opens up the possibility of manufacturing the sealing strip and the frame profile from materials with differing coefficients of expansion.

Preferably the frame profile is of substantially U-shaped cross-section with its limbs converging towards theirfree ends and the sealing strip is curved in substantially a U-shaped or tubular configuration. With this construction the sealing strip can contact the cooperating sealing surface over a relatively broad contact area and the arch region of the sealing strip has a relatively small degree of curvature.

In an alternative construction the frame profile is of part-circular cross-section and the sealing strip abuts the whole or a part of the inner surface of the frame profile. This construction enables a greater degree of curvature of the arch region of the sealing strip to be achieved if this should be required.

In one embodiment the seal includes guide pegs secured to one or both limbs of the frame profile and passing through elongate holes in the sealing strip. This construction ensures that the sealing strip cannot slip out of the frame profile but does not restrain the sealing strip from sliding along the support surfaces of the frame profile.

One embodiment of the invention includes one or more resilient support strips beneath the sealing strip and within the space defined by the limbs of the frame profile. The support strips may be produced from a flat strip material in a manner similarto the sealing strip and may be fitted into the frame profile either before or at the same time as the sealing strip itself by bending it by hand or with the aid of a simple mechanical device. The use of such support strips enables the contact pressure of the sealing strip against the limbs of the frame profile to be increased. Furthermore, the sealing strip can engage the support strip or strips in its arch region after a predetermined deformation by reason of its contact with the opposed sealing surface which results in an increase in the sealing force and permits the deformation of the sealing strip to be limited.

If the gas for which the valve is to be used is particularly dusty it may be convenient to provide resilient dust deflecting strips between the sealing strip and the limbs of the frame profile.

In the preferred embodiment the seal is polygonal, especially rectangular, and the sealing strip comprises a plurality of interconnected segmental strips. With those valves which are subject to thermal stress it is preferred that each side of the seal 2 GB 2 116 679 A 2 comprises two or more segmental strips which are spaced apart by an expansion joint formed by a resilient cover strip beneath the segmental strips.

Conveniently two segmental strips with mitred ends abut at each corner of the polygon and are con nected together by a resilient cover element beneath the segmental strips.

If the valve is of gate valve type the mitred edges of the segmental strips at the corners conveniently contact each other over their entire length and the 75 cover element connecting them comprises a strip firmly connected to both segmental strips in the central region of the butt joint. If the valve is of flap type with the seal carried by the valve housing, the mitred edges of the segmental strips at the corners conveniently diverge inwardly and the cover ele ment comprises a strip firmly connected to both segmental strips in the outer region of the buttjoint.

If the seal is carried bythe valve flap, the mitred edges of the segmental strips atthe corners conve niently diverge outwardly and the cover element comprises a resilient wire secured by means of a bracket which is firmly connected to both segmental strips in the inner region of the butt joint.

The frame profile accommodating the sealing strip 90 may be welded to either the valve member orvalve housing which enables separate securing means to be omitted. Alternatively, the frame profile can be connected to the valve by means of screws which enables the sealing strip to be inserted and removed 95 from the frame profile remote from the valve. Whilst it is preferred that the two limbs of the frame profile be integral, the frame profile may also comprise two individual profiles each having one limb freely engaged by the sealing strip. The longitudinal edges 100 of the sealing strip may be curved inwardly so that the sealing strip is better supported by the frame profile.

Further features and details of the present inven tion will be apparent from the following description of certain specific embodiments which is given by way of example with reference to the accompanying drawings, in which:

Figure 1 is a sectional elevation of a shut-off gate valve with two seals on the valve housing in accordance with the invention shown in the open position; Figure 2 is a view similar to Figure 1 showing the valve in the closed position; Figure 3 is a sectional elevation of the area 115 designated Ill in Figure 1 showing the seal on an enlarged scale; Figures 4to 7are views similar to Figure 3 showing modified constructions of the seal; Figure 8 is an end elevation of the corner region of 120 the seal of the shut-off gate valve of Figures 1 and 2 shown on an enlarged scale; Figure 9 is a sectional elevation of a shut-off gate valve with a single seal on the housing in accordance with the invention, shown in the open position; Figure 10 is a sectional elevation of a shut-off gate valve whose sliding plate is provided on both sides with a seal in accordance with the invention, shown in the closed position; Figure 11 is a sectional elevation of a shut-off 130 valve shown in the closing position with a seal on the housing in the upper half of the figure and a seal on the flap in the lower half of the figure; Figure 12 is an end elevation of the corner region of the seal of the valve of Figure 11 shown on an enlarged scale; Figure 13 is a sectional view of a modified construction of the housing seal of Figure 11 shown on an enlarged scale; Figure 14 is a view similar to Figure 11 of a modified construction of flap valve having both a housing and flap seals in accordance with the invention, shown in the closed position; Figure 15 is a view similar to Figure 12 showing the seal of the valve of Figure 14 on an enlarged scale; and Figures 16 to 18 are scrap sectional views of further modified constructions of housing seal.

The shut-off gate valve shown in Figures 1 and 2 comprises a rectangular housing 1 and a sliding plate 2 which is slidable between two rectangular seals 3 and 4 carried by the housing. The seals each comprise a support frame of straight profiles 5 into which sealing strips 6, which are also straight, are fitted, as seen in Figure 3.

The frame profile 5 is constructed as a U-shaped metal plate profile with limbs 7 and 8 converging towards the sealing plane and a flat web 9 connecting them together which is welded to a housing wall 10 of the gate valve housing 1.

The sealing strip 6 comprises an elastic metal plate strip which is flat before its assembly (shown in chain-dotted lines in Figure 3). Preferably the metal strip is 0.2 to 0.5 mm thick and of refined steel which is elastic by virtue of its inherent hardness (due to its carbon content) or by virtue of cold rolling. The breadth of the sealing strip 6 is so selected that after its assembly into the frame profile 5 its longitudinal edges 11 and 12 engage the limbs 7 and 8 of the frame profile 5 over a sufficient area. The sealing strip 6, which is readily flexible, is slightly distorted by hand or with a suitable mechanical device and fitted into the frame profile 5. The sealing strip 6 is thus biassed into contact with the limbs 7 and 8 of the frame profile 5 by virtue of its bending elasticity and in the sealing region between the ends of the limbs 7 and 8 adopts the shape of an elastic arch 13 with the limbs 7 and 8 of the frame profile 5 extending approximately tangentially to the arch 13.

The sealing strip 6 is securely retained in the frame profile 5 by the contact pressure of its longitudinal edges 11 and 12 against the limbs 7 and 8. The arch region of the sealing strip is, however, elastically deformable by reason of the free engagement of the strip with the limbs 7 and 8 when it is stressed by the opposing sealing surface of the valve, which in this case is afforded by the sliding plate 2. The sealing strip 6 is thus able to exert a sealing force which is always sufficient on the opposing sealing surface and at the same time to abut this surface in a sealing manner despite any irregularities or foreign bodies lying between them which may be present. The deformability of the sealing strip will depend on its properties and thus its contact area with the opposing sealing surface may be varied as may also the 3 GB 2 116 679 A 3 sealing pressure by varying the properties of the sealing strip.

The seal of Figure 4 differs from that shown in Figure 3 merely in that the sealing strip 6 is provided with rounded corners 14 and 15 on the longitudinal edges 11 and 12. The sealing strip thus abuts the web 9 of the frame profile 5 on both its longitudinal edges which ensures a reliable support of the sealing strip 6 without impairing its resilient defor- mability.

In the embodiment of Figure 5, the seal 3 includes a support strip 16 which is produced in a manner similar to the sealing strip 6 from a resilient material which is flat before its assembly into the frame profile 5. The support strip 16 is fitted into the frame profile 5 by bending the strip by hand or by means of a mechanical device either before or at the same time as the sealing strip 6. The support strip serves to increase the contact pressure of the sealing strip 6 against the limbs 7 and 8 of the frame profile 5 in that the longitudinal edges 11 and 12 of the sealing strip 6 are additionally pressed against the limbs 7 and 8 of the frame profile 5 by the longitudinal edges 17 and 18 of the support strip 16.

The frame profile 5 is connected to the housing wall 10 with the aid of bolts 19 spaced apart in the longitudinal direction which make it possible to remove the frame profile 5 from the gate valve housing 1 in order to insert or remove the sealing strip remote from the valve.

The embodiment of Figure 6 differs from the embodiment of Figure 5 merely in that the sealing strip is provided along its longitudinal edges 11 and 12 with resilient dust deflecting strips 20 and 21 which are connected to the sealing strip between the latter and the associated limb of the frame profile by spot welding at 22 and have a curved edge 23 on the longitudinal edge nearest, and extending over, the free edge of the associated limb 7 or 8. The dust deflecting strips 20 and 21, in the assembled state, sealingly engage the inner surfaces of the limbs 7 and 8 and thus prevent dust or other dirt from being able to enter the region between the sealing strip 6 and the limbs 7 and 8.

The seal shown in Figure 7 includes a part-tubular frame profile 5 welded to the housing wall 10 and guide pegs 24 spaced apart in the longitudinal direction which, in the assembled state, are guided through elongate holes 25 in the sealing strip 6. The guide pegs 24 serve to prevent the sealing strip 6 slipping out of the frame profile 5 without impairing its free engagement with the support surface of the frame profile 5. As an alternative to the guide pegs 24 hooks or the like can be used.

As may be seen in Figure 8, the sealing strip of each of the housing seals 3 and 4 is divided in the longitudinal direction so that each side comprises one or more substantially rectangular segmental strips 26a or 26b separated from two mirror-image segmental strips 27a and 27b at the corners by expansion joints 28. The segmental corner strips 27a and 27b are mitred at the corners and engage to form an obliquely extending butt joint 29. The expansion joints 28 and the butt joints 29 are sealed with resilient cover strips 30 and 31 beneath them which are secured by spot welding at 32 and 33 respectively to the segmental strips 27a and 27b. The cover strips 30 for the expansion joints 28 are welded to the segmental strips 27a and 27b on both sides in the central region of the butt joints only in order to permit the segmental strips 27a and 27b to deform freely in the corner regions.

The cover strips 30 at expansion joints between two adjacent rectangular segmental strips 26a and 26b are constructed similarly to those at the illustrated expansion joints between the rectangular segmental strips 26a and 26b and the mitred segmental strips 27a and 27b. They are each welded on one side to one only of the two adjacent segmental strips 26a and 26b.

The shut-off gate valve shown in Figure 9 differs from the valve of Figures 1 and 2 merely in that it is provided with only one housing seal 4. This is constructed identically to the seals of the valve of Figures 1 and 2 and will therefore not be described in more detail. Whilst in the valve of Figures 1 and 2 the sealing of the slider opening in the open position of the valve is effected by cooperation of the two housing seals 3 and 4, in the embodiment of Figure 9 by the co-operation of the single housing seal 4 with the housing wall 10 of the valve. This means that in the latter case the sealing strip of the housing seal 4 must deform about twice as much as the sealing strips of the housing seals 3 and 4 of the valve of Figures 1 and 2 when the sliding plate 2 is slid into the closed position.

In the cut-off gate valve of Figure 10, the sliding plate 2 carries two rectangular seals 3 and 4 which, in the closed position, of the slider are pressed against the opposing housing walls 10. The construction and operation of this valve are analogous to those of the valve of Figures 1 and 2 and will therefore not be described in more detail.

The shut-off flap valve shown in Figure 11 com- prises a flap housing 34 and a rectangular flap 35 with a rotary shaft 36 mounted in the flap housing 34. This Figure shows different embodiments in its upper and lower halves. In the embodiment shown in the upper half, the flap housing. 34 is provided with a rectangular seal 37 which, analogously to the seals 3 and 4 of the valve of Figures 1 and 2, comprises a frame profile 5 and a sealing strip 6. On closing of the flap the latter is compressed bythe opposing sealing surface 38 by the flap edge and forms with its a reliable seal even with hot or dusty gases. In the embodiment in the lower half of the Figure, the seal is carried by the flap and co-operates with the sealing surface afforded by the housing 34.

As may be seen in Figure 12, the seal 37 is so constructed at its corners that the corner edges 39a and 39b or the abutting sealing strips 40a and 40b in the region of the mitre line diverge inwardly in order thatthe sealing strips 40a and 40b may deform freely in the corner region. The resulting buttjoint41 is sealed by an oblique resilient cover strip 42 beneath it. The latter is firmly connected in the outer region of the butt joint to both sealing strips 40a and 40b by means of spot welding at 40.

The seal 37 shown in Figure 13 differs from the housing seal shown in Figure 11 merely in that the 4 GB 2 116 679 A 4 frame profile 5 is provided with a securing web 44 with the aid of which the frame profile 5 is secured by screws (not shown) to a fastening flange 45 on the flap housing 34. Thus the seal 37 may be easily removed from the flap valve and the sealing strip 6 inserted or removed from the frame profile remote from the valve.

The shut-off flap valve shown in Figure 14 differs from that in Figure 11 merely in that the flap 35 carries a rectangular seal 46 which co-operates with a similar seal 37 carried by the flap housing 34. The seal 46 is screwed do the flap disc in a manner similar to the housing seal 37 in Figure 13. As may be seen in Figure 15, this seal is so constructed in the region of its corners that the mitred corner edges 47a and 47b of the abutting sealing strips 48a and 48b diverge outwardly. The resultant butt joint 49 is sealed by an oblique resilient wire 50 beneath it which is secured by means of a bracket 51 welded to both sealing strips 48a and 48b in the central region of the butt joint.

The seals of Figures 16 and 17 differ from the seals of Figures 11 and 14 merely in that in both cases the frame profile 5 comprises two individual profiles arranged parallel to one another. In the embodiment of Figure 16 these are constructed as angle profiles 52a and 52b which are screwed to the flap housing 34 and each have a support limb 7 and 8 respectively for engagement with the sealing strip 6.

In the embodiment of Figure 17 the individual profiles 53a and 53b are constructed in the manner of tracks. They are also screwed to the flap housing 34 and each also have a support limb 7 and 8 respectively for the sealing strip 6.

In the embodiment of Figure 18 the breadth of the sealing strip 6 is so selected that in the assembled state it adopts a tubular shape with its edges overlapping. In this case, guide pegs 24 are arranged centrally in the U-shaped carrier profile 5 and the sealing strip 6 is provided on both edges with elongate holes 25 through which the guide pegs 24 pass.

It will be appreciated that many modifications may be made to the illustrated embodiments and that these may be combined in any appropriate manner. Thus the sealing strip may be manufactured from plastics material, rubber or any other suitable resilient material. Further, it is also possible to provide the frame profile 5 on both sides with guide pegs for the sealing strip in a manner similar to the embodiment of Figure 7.

Whilst the seal has been described as rectangular, it and thus the valve member may also have other polygonal shapes, e.g. hexagonal or octagonal and the seal may also be used with louver flap valves.

Claims

1. A valve for gaseous media including a valve housing and a substantially planar valve member which is movable with respect to the housing to throttle or shut off gas flow therethrough, the housing and/or the valve member carrying a seal arranged to form a substantially gas-tight seal, when the valve member is in the closed position, with a sealing surface, the or each seal comprising a frame profile having two limbs which are directed towards the associated sealing surface when the valve member is in the closed position and a resilient sealing strip which is bent and so positioned that its longitudinal edges freely engage the said limbs and its central portion forms an arch extending out of the space defined by said limbs.

2. Avalve as claimed in Claim 1 in which the frame profile is of substantially U-shaped crosssection with its limbs converging towards theirfree ends and the sealing strip is curved in substantially U-shaped ortubular configuration.

3. Avalve as claimed in Claim 1 in which the frame profile is of part-circular cross-section and the sealing strip abuts the whole or a part of the inner surface of the frame profile.

4. Avalve as claimed in anyone of Claims 1 to 3 including guide pegs secured to one or both limbs of the frame profile and passing through elongate holes in the sealing strip.

5. Avalve as claimed in anyone of Claims 1 to 4 including one or more resilient support strips beneath the sealing strip and within the space defined by the limbs of the frame profile.

6. Avalve as claimed in anyone of Claims 1 to 5 including resilient dust deflecting strips between the sealing strip and the limbs of the frame profile.

7. Avalve as claimed in anyone of Claims 1 to 6 in which the seal is polygonal and the sealing strip comprises a plurality of interconnected segmental strips.

8. Avalve as claimed in Claim 7 in which each side of the seal comprises two or more segmental strips which are spaced apart by an expansion joint formed by a resilient cover strip within the space defined by the limbs of the frame profile.

9. Avalve as claimed in Claim 7 orClaim 8 in which two segmental strips with mitred ends abut at each corner of the polygon and are connected together by a resilient cover element within the space defined by the limbs of the frame profile.

10. Avalve as claimed in Claim 9 which is of gate valve type and in which the mitred edges of the segmental strips at the corners contact each other over their entire length and the cover element connecting them comprises a strip firmly connected to both segmental strips in the central region of the buttjoint.

11. Avalve as claimed in Claim 9 which is of flap type and in which the seal is carried by the valve housing and in which the mitred edges of the segmental strips at the corners diverge inwardly and the cover element comprises a strip firmly con- nected to both segmental strips in the outer region of the butt joint.

12. Avalve as claimed in Claim 9 which is of flap type and in which the seal is carried by the valve flap and in which the mitred edges of the segmental strips at the corners diverge outwardly and the cover element comprises a resilient wire secured by means of a bracket which is firmly connected to both segmental strips in the inner region of the butt joint.

13. Avalveasclaimed in anyoneof Claims 1 to 12 in which the frame profile accommodating the V GB 2 116 679 A 5 sealing strip is welded to the valve member or housing.

14. Avalveasclaimed in anyone of Claims 1 to 12 in which the frame profile accommodating the sealing strip is screwed to the valve member or housing.

15. Avalveasciaimed in anyone of Claims 1 to 14 in which the frame profile comprises two individual profiles, each having one limb freely engaged by the sealing strip.

16. Avalve as claimed in anyone of Claims 1 to 15 in which the longitudinal edges of the sealing are curved inwardly.

17. A valve for gaseous media substantially as specifically herein described with reference to Figures 1 and 2 in combination with any one of Figures 3 to 7 and/or Figure 8, or with reference to any one of Figures 9 to 11 alone or in combination with Figure 12 and/or Figure 13 or with reference to Figure 14 alone or in combination with any one of Figures 15 to

18.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1983. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.